Motor deficit of hand and arm movements in manifest hepatic encephalopathy before and after therapy with L-ornithin-L-aspartat

Background and Aims: Impaired hand function is a frequent finding in movement disorders. Grip force analysis is a highly sensitive method to document even subtle impairments of finger force control and may be used both as a diagnostic tool and for the objective evaluation of treatment in neurological movement disorders. Hepatic encephalopathy (HE) is characterized by a large variety of symptoms including postural tremor or motor deficit of hand and arm movements. It is unclear if an improvement can be obtained by medical therapy. The present study was designed to quantitatively assess the influence of HE on grasping and elementary diadochokinetic movements and to evaluate the effect of treatment with L-ornithin-L-aspartat (LOLA).

Methods: 25 patients with liver cirrhosis and manifest HE (grades I and II, West-Haven criteria) were enrolled in a prospective clinical trial of intravenously administered LOLA administered in a dose of 20g/d and infused intravenously during 6 consecutive days. HE was evaluated by psychometric tests (number connection tests A, B; figure connection tests A, B; line-tracing-test) and critical flicker frequency (CFF) before and after LOLA-therapy. Two different diadochokinetic (forearm diadochokinesis, finger tapping) and three cyclic vertical arm movements with a hand held instrumented object at three different speeds were tested in patients with manifest HE prior to and following medical treatment with LOLA and healthy control subjects. Movements were measured three-dimensionally and the kinematics of joint angles were analyzed (CMS70, Zebris, Isny).

Results: The patients' measures of movement speed and symmetry appeared abnormal and detailed kinematic analysis revealed deficits in several measures of movement variability compared with healthy controls. Interestingly, patients increased their speed of grasping movements if extrinsic triggers of the moving object were used. LOLA-treatment resulted in individual effects upon diadochokinetic movements with an improvement of both the grasp and lift components of the task. LOLA showed significant efficacies in patients with manifest HE with respect to improvement in psychometric test times and CFF.

Conclusions: These data suggest that manifest HE contributes to motor deficits of elementary diadochokinetic and grasping movements dependent on the severity of HE. Grip force analysis may provide an additional test to quantify the clinical response to LOLA-treatment.